KR20140085401A - A tool for chip removing machining as well as a part and threaded joint therefor - Google Patents

Abstract

A screw-type joint comprises a female screw and a male screw in a screw thread shape where a cutting tool and a loose top of the same are interacting to comprise two parts detachably connected. A profile form of each screw thread is determined by the upper part and two flanks and limits a screw-type groove having a bottom part. A first flank is inclined for a central axis line of the tool at a first angle which is smaller than a second angle in which the second flank is inclined for the central axis. Therefore, a tensile force larger than a compression force can be applied on the screw-type joint while preventing damage to the screw thread to reinforce the screw thread compared with the screw thread having a symmetrical profile form.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a tool part and a threaded joint for chip removing machining,

In a first aspect, the present invention relates to a tool for chip removal or cutting, the type of tool comprising two parts oriented along a central axis and detachably connected to each other via a threaded joint.

On the other hand, the threaded joint comprises a female screw located near the inlet of the hollow in one of the two parts and a male screw located near the free end of a male-like pin included in the other part. Each screw includes a helical thread which includes an upper portion and a pair of opposing flanks defining a helical groove having a bottom portion. While the pin is being screwed into the hollow, the first flanks of the male thread facing away from the ends of the pin are threaded into the first flanks of the female threads facing away from the mouth of the hollow, The second flank of the male thread facing towards the free end presses against the second flank of the female thread toward the mouth.

In another aspect, the present invention also relates to a detachable portion for such a tool.

Indeed, this type of tool can be used to machine metal work such as steel and steel alloys, iron, aluminum, titanium, and the like.

An associated rotary cutting tool includes two parts connected by a boundary or a joint. For example, the body and the cutting body or the wear parts are detachably connected together. Indeed, such a tool may be in the form of, for example, a drill or milling cutter, such as a shank-end mill or profile mill. In modern processing tools, the body is expensive and therefore can not be coupled to the cutting body for economical reasons, and this cutting body has a limited service life as a wear part. That is, it is desirable to make a suitable cutting body in the form of a replaceable individual element unit after the wearer has called "loose top" so that the body can be used for a longer period of time.

The development of loose-top tools for rotary machining has recently become significant, resulting in a number of different tool constructions, which are different from each other in the interface or joints between the loose tower and the main body. As long as the loose top tool has been the subject of numerous suggestions for design considerations, the design of the boundary between the loose top and the body becomes a technical problem that is difficult to handle. Thus, a number of different difficulties have been taken into account, as well as the situation where the loose top and body are made of separate pieces of material from each other, as well as the situation where the tool must operate under extreme external conditions such as strong heat dissipation, . In particular, miniature tools such as shank-end mills and profile mills are subject to a variety of different stresses, which vary most in different functional states. Thus, for example, the loose top of the profile mill, i. E., The hard, removable cutting body, receives radial forces acting on the loose tower at different angles as well as axial tension and compressive forces. Therefore, when designing a boundary or joint that actually works between the loose top and the body, it is necessary to consider the subtle balance of many conditions that can often flash.

In related tools, threaded joints have been used successfully to connect the loose top to the body. Typically, the rear male pin is formed in a loose tower having a conical or cylindrical male thread, which can be combined with a corresponding male thread in a hollow having an inlet at the front end of the body. In the related tool, the rear pin of the loose tower is formed with a cylindrical outer guide surface at the front and rear of the male thread of the pin. When the male screw is tightened on the female thread of the main body, the guide surface engages with the inner cylindrical guide surfaces at the front and rear of the female screw to prevent the loose tower from warping, especially when subjected to radial stress, to stably fix the loose tower . In one associated work tool, the threaded joint has a conical screw. The feature of this threaded joint is that the top of one of the threads is in surface contact with the groove bottom of the other screw in order to secure the loose top and to prevent warping of the loose top. This is theoretically an interesting idea since the number of interactive guide surfaces can be reduced. However, in practice, manufacturing two parts of the tool requires too high dimensional accuracy to economically realize a series of production. In the related cutting tool, the loose top includes a single conical guide surface adjacent to the male thread of the pin.

Commonly known in the prior art for threaded joints for cutting tools, the force exerted by the screw of the loose tower moves in the axial direction (when the screw is pressed) and when the screw is tightened (when the screw is pulled And when the screw is subjected to an excessive load due to too strong tightening, it can be deformed.

The present invention is directed to overcoming the disadvantages of the above-mentioned cutting tool using a threaded joint between two detachably connected parts and to providing an improved tool. Accordingly, there is provided a tool including a threaded joint capable of generating a large tightening force without damaging the durability of the thread. That is, a tool threaded joint is provided that optimizes the use of each thread material so that the pulling flank of the male thread can transmit a large tension to the female thread while avoiding damage to the thread. It also provides a tool including a threaded joint that allows quick and simple connection and disconnection of two parts of the tool. In a particular aspect, a rotating tool of two parts, a main body and a loose top, is provided, and the loose top can be fixed to the main body in a stable manner and still allows a quick and simple replacement.

According to one embodiment of the present invention, a tool for chip removal machining is provided. The tool includes a first portion and a second portion oriented along a common center axis and a threaded joint releasably connecting the first and second portions to one another. The threaded joint includes a female thread disposed at an inlet of the hollow portion of the first portion, a male thread disposed at the free end of the male pin of the second portion, and individual threads. A tool for chip removal processing, comprising: a first portion and a second portion oriented along a common axis; and a threaded joint detachably connecting the first and second portions to each other, the threaded joint comprising: , A female screw disposed at an inlet of the hollow portion of the first portion, a male screw disposed at the free end of the male pin of the second portion, and an individual screw having a profile shape defined by the upper and the two flanks, The first flanks of the male thread facing away from the free end of the pin and the first flanks of the female thread facing away from the inlet of the hollow are pressed against each other while the pin is threaded into the hollow, A second flank of male thread facing towards the free end and a second flange of female thread towards the mouth are threaded off the hollow And the first flank of the female thread and the male thread is inclined with respect to the central axis at a first angle smaller than the second angle which the second flank is inclined with respect to the central axis.

According to another embodiment of the present invention, there is provided a tool portion for chip removal machining. Said portion including a male thread disposed adjacent a free end of a male pin extending along a central axis, said male thread comprising a helical thread with a peripheral upper portion and a pair of opposite flanks, said flange comprising a helical groove Wherein the first one of the pair of opposing flanks is directed toward the free end of the pin and is inclined with respect to the central axis at a first angle smaller than the inclination of the second angle with respect to the central axis of the second flank of the pair of opposing flanks have.

According to another embodiment of the present invention, a threaded joint is provided in which the first portion and the second portion detachably connect to each other along a common central axis. A threaded joint detachably connecting a first portion and a second portion along a common central axis, the first portion having an inlet of the hollow portion and the second portion including a male pin extending to a free end, Said threaded joint comprising a female thread disposed on a hollow portion of a first portion and a male thread disposed on a male pin of a second portion, said female thread comprising a female helical groove having a first bottom portion disposed on opposite sides of a first peripheral upper portion, Wherein the first flank of the helical female thread is facing away from the inlet of the hollow and the second flank of the helical female thread has a first profile shape defined by first and second flanks defining a second helical female thread, The flank is directed toward the inlet of the hollow portion and the male screw is disposed on either side of the second peripheral upper portion to define a first and a second helical groove having a second bottom portion, Wherein the first flanks of the helical male threads face toward the opposite side of the free ends of the male pins and the second flanks of the male threads form the free ends of the male pins The first flank of the helical male threads and the first flanks of the helical female threads being pressed against each other while the fins are threaded into the hollow and the second flank of the helical male thread and the second female flange of the helical female thread The two flanks are pressed against each other while the pins are threaded out of the hollow, the first flank of the helical male thread and the helical female thread being inclined at a first angle to the central axis, and the second flank of the helical male thread and the helical female thread The flanks are inclined with respect to the central axis at a second angle greater than the first angle.

According to another embodiment of the invention, an interlocking thread of a threaded joint having a different flank is formed. In particular, the first flank of each thread acting to pull the thread temporarily has a smaller flank angle than the flank angle of the second flank, which acts to pressurize when the thread is unscrewed. In this way, each thread gets proportionally larger amounts of material in the inner region of the pressing flanks, i.e., the threads are reinforced in the region of the pressing flanks. Thus, the resulting tensile force exerted on the threads during the threading is absorbed and dispersed in the extra reinforcing material portion. An advantage of this is that a tension greater than the compressive force can be applied to the threaded joint without damaging the thread.

According to the invention, a tensile force greater than a compressive force can be applied to the threaded joint while preventing damage to the thread, so that the thread can be strengthened as compared to a thread with a symmetrical profile shape.

1 is a partial cross-sectional view showing two portions of a shank-end mill configuration according to one embodiment of a cutting tool.
Fig. 2 is a perspective enlarged view showing a loose top included in the tool, spaced apart from the partially cut body of the cutting tool shown in Fig. 1;
3 is a partial side view showing a pin included in the loose tower having a male thread partially coupled to the inside of the hollow portion of the main body provided on the female screw.
Figure 4 is a similar side view showing a tightened loose top with a male thread integrally associated with the female thread of the body.
5 is a side view showing only a loose top.
Figure 6 is an enlarged longitudinal view through a portion of the body, showing a schematic view of the female screw;
7 is an enlarged longitudinal view through a portion of a pin of a rouge top showing a schematic view of a male screw;
8 is a further enlarged longitudinal sectional view showing a plurality of threads included in the male screw;
9 is a longitudinal sectional view showing the interaction of the female screw and male screw during screw tightening.
10 is a longitudinal sectional view showing the interaction of a female screw and a male screw during screw threading;

Figures 1 and 2 illustrate a tool for chip removal machining of a metal workpiece, for example. The tool comprises two parts, for example a main body 1 and a so-called loose top 2 in the form of a milling cutter, which are mutually detachably connected via threaded joints. As shown, the body 1 is of a long, narrow shape and includes a front end 3 and a rear end 4. The shape of the main body 1 is characterized by rotational symmetry. For example, the outer surface of the main body 1 includes a cylindrical surface 5 as well as a conical surface 6. [ The body 1 may be tubular or include a central through hole 7 (see Fig. 2), or may be a solid body.

The loose top 2 includes a front head 8 and a rear fin 9. The male screw 10 is formed in the rear pin 9 to interact with the female screw 11 of the hollow portion 12 having an inlet at the front end 3 of the body 1. [ This inlet is surrounded by an annular shoulder surface 13 which may be flat. A plurality of cutting edges 14 and 15 are formed in the head 8 of the rouge top. Some of the cutting edges 15 are helical and extend along a virtual rotationally symmetrical shell surface and the other cutting edges 14 are straight and may be located on the end surface of the front head 8. [

As best seen in Fig. 5, the head 8 has an annular rear contact surface 8a, and the head abuts against the shoulder surface 13 and is raised. In addition, the two planes 8b can be formed in the front head 8 to form a key grip.

The loose top 2 and the body 1 are oriented along a common central axis C and the assembly can be rotated in the direction of the arrow P (see Figures 1 and 2).

In the illustrated embodiment, the two screws 10, 11 have a conical base shape. Also, a pair of mutually interacting guide surfaces 16, 17 are located in front of each screw and are in the form of rotational symmetry. For example, the guide surfaces 16, 17 can be cylindrical and can be accurately fitted together.

In an embodiment, the interacting guide surfaces 18, 19 are, for example, in the form of a rotationally symmetrical cylinder and are arranged behind each screw. The surfaces 18,19 can be accurately fitted to each other even if the requirements for their dimensional accuracy are somewhat smaller than those for the front guide surfaces 16,17.

Alternatively, the fit between the front guide surfaces 16, 17 can preferably be interference fit, in which case the diameter of the surface 16 is slightly larger than the inner diameter of the guide surface 17.

The advantage of the screws 10 and 11 having a basic conical shape compared to the cylindrical shape is that the male screw 10 can be coupled to a sufficient distance into the interior of the female screw 11 before the screws are engaged with each other, It is. This means that only one or several screw turns need to be rotated so that the male screw 10 is finally tightened in the female screw 11. [ Thus, as shown in Fig. 4, from the state shown in Fig. 3, the loose tower 2 only needs to rotate by about 1.5 turns in order to reach the finally clamped state.

6 to 10, Fig. 6 shows the structure of the female screw 11, and Fig. 7 shows the structure of the male screw 10. In Fig. 7, imaginary busbar 20 defining the shape of the general cone (or truncated cone) of male screw 10 is extended by an angle?, Also referred to as cone angle. As shown, the conical angle [gamma] is 6 [deg.]. The screw 10, also referred to as the spiral ridge 10, has a profiled profile defined by an upper portion 21 and two flanks 22 and 23, the two flanks having a helical groove 24 with a bottom portion 25, .

In a similar manner, the female thread comprises a thread 11 and has a profile shape defined by an upper portion 21 and two flanks 22a, 23a, the two flanks having a helical groove 24a. When the male thread 10 is tightened into the female thread 11, the first flank 22 of the male thread 10, which faces away from the free end 9a of the pin 9, And presses the first flank 22a acting. The flank 22a faces away from the inlet of the hollow portion 12. [ When the screw is loosened, the second flank 23 of the male thread 10 presses the second flank 23a, which interacts with the female thread 11. Since the first flank 22, 22a acts in a screwed manner, this is also referred to as a "pulling flange ", and the flanks 23 and 23a may be referred to as a" pressing flange ".

Each pulling flank 22,22a of each thread is inclined with respect to the central axis C by an angle alpha smaller than the angle beta of the pressing flanks 23 and 23a with respect to the central axis C. [

In the embodiment shown, angle alpha is about 108 deg and angle beta is about 129 deg. However, angle (?) And angle (?) Are not limited to this angle. In particular, the flank angle? Of the pulling flank 22 of the male thread 10 can be 100 ° or more and 120 ° or less. Preferably, the angle alpha may range from 104 to 115 degrees. The corresponding flank angle of the pulling flank 22a of the female thread 11 should be equal to the flank angle of the pulling flank 22 of the male thread 10 irrespective of its specific value. Therefore, surface contact between the pulling flank 22, 22a is ensured in accordance with the screwing.

The flank angle beta of the pressing fences 23 and 23a is not less than the angle alpha and may deviate from the above angle of 129 deg. In practice, the angle (?) Is not less than 115 ° (angle (?) Less than 115 °) and not more than 150 °. Preferably, the angle (?) Should be in the range of 120 to 140 ° or 124 to 134 °. In practice, the angle? May be greater than 15 占 more than the angle?.

Since the need for surface contact between the pressing flanks 23 and 23a is less than the need for surface contact between the pulling flanks 22 and 22a, the flank angles of the pressing flanks 23 and 23a may be different. In practice, the flank angle of the pressing flanks 23a may be slightly larger than the flank angle of the pressing flanks 23. [

Reference is made to Fig. 8 showing the configuration of the male thread 10 in more detail. The cross-sectional view of FIG. 7 as well as the cross-sectional view of FIG. 7 is seen in the axial direction A-A cross-section of FIG.

As best shown in Fig. 8, the upper portion 21 of the thread 10 is a surface having a predetermined width, which is determined by the length of the straight line forming part of the bus bar 20 defining the imaginary conical surface. The upper surface 21 is continuous with the flanks 22, 23 through the convex flanks 26, 27. In a similar manner, the flank 22, 23 leads to the bottom 25 of the groove through the concave round cloth 28, 29. In this example, the grooves 24 have the same depth along their entire length, since the groove bottom 25 abuts the bus bar 30 parallel to the bus bar 20.

The flank of the imaginary thread profile is shown by the dashed line 31, which is symmetrical if the flank angles are equal on both sides of the thread. If the pressing flank 23 is formed with a larger flank angle than the pulling flank 22, the excess surface area of the material present in the actual flank 23 as compared to the imaginary flank 31 will cause it to be adjacent to the pressing flank 23 A stiffener is provided. The resulting force acting on the thread 10 during thread tightening is represented by R, which is the vector sum of the axial component K _a and the radial component K _r . By virtue of the surplus stiffener of the pressing flange 23, the force R can be absorbed and dispersed along a significantly larger surface area than if the threads had the conventional symmetrical shape, i.e. the imaginary flanks 31.

Typically, the groove 24a of the female screw 11 has a profile that is larger than the profile of the male screw threads 10, and therefore there is play between the screws. This is best seen in FIGS. 9 and 10, where FIG. 9 shows the threaded joint in the threaded configuration and FIG. 10 shows the threaded joint in the threaded release. In both cases, there is a play between the tops 21, 21a of each thread and the groove bottoms 25, 25a in which each thread is contained. The pulling flank 22 of the male thread 10 presses the pulling flank 22a of the female thread 11 so that the pressing flanks 23 and 23a do not come into contact with each other at the time of screwing according to Fig. 10, the situation is reversed, that is, the pressing flanks 23 of the male threads 10 press the pressing flanks 23a of the female threads 11, and the pulling flanks 22, 22a They are not in contact with each other.

By forming the two screws with an asymmetric profile as described above, reinforcement is achieved in terms of the thread, which must absorb the tension (whether it is the acting force of the male thread 10 or the reaction force of the female thread 11) do. Thus, the threaded joint can withstand a tension greater than the compressive force required to loosen the loose top 2. In other words, the function of the threaded joint is optimized, that is, the loose tower 2 is stably fixed by a large clamping force, which is more important than the large compressive force for screw loosening and preventing thread damage. It should be noted here that, particularly when the screw has a conical base, the screw loosening can generally be done with a force that is more appropriate than screw tightening. Another advantage of this embodiment of the threaded joint is that several identical threaded joints are realized with a few (actually three to five) thread turns, and tightening and loosening is effected through short and limited rotational movements (one or two turns), respectively It is possible.

In the illustrated embodiment in which the tool is in the form of a shank-end mill, the entire loose top 2 can be made of a single hard material, such as a cemented carbide, and at least the front portion of the main body 1 is relatively soft Or the like.

Alternatively, the threaded joint may be used to detachably connect other parts included in the cutting tool in addition to the loose top and rotatable body. As noted above, the male screw may comprise a landscaping alloy and the material of the female screw may comprise steel as described above, or alternatively the two screws may be made of the same or similar material, such as steel, for example. In addition, the shape of the two interacting screws may be modified in various ways. For example, the screw may be conical in shape as described above, or alternatively the basic form of the screw may be cylindrical. Also, if the screw is a cone, the cone angle may be greater or less than 6 degrees. Further, the number of thread turning parts and the thread pitch can be changed, respectively. Also, in the case of the illustrated shank-end mill, the special guide surfaces in front of and / or behind the two screws can be omitted. Also, the required play between the male and female threads may vary depending on the type of tool, including, for example, threaded joints. In addition, the number of thread starting portions may vary.

Thus, for example, in a rotary tool, such as a shank-end mill, a threaded joint is self-locking when a screw is provided such that the screw thread tends to be tightened into the female screw by torque transmission between portions of the tool, I have sex.

While the present invention has been described with reference to certain preferred embodiments, various modifications, alterations, and changes to the described embodiments are possible without departing from the scope and spirit of the invention, as defined in the appended claims and their equivalents. Therefore, the present invention is not limited to the embodiments described, but has the entire area regulated by the following claims.

Claims (16)

As a tool for chip removal machining,
A first portion and a second portion oriented along a common axis, and
And a threaded joint for detachably connecting said first portion and said second portion to each other, said threaded joint comprising:
A female screw disposed at an inlet of the hollow portion of the first portion,
A male screw disposed at the free end of the male pin of the second portion, and
The first flanks defining a spiral groove having a bottom and having a profile shape defined by the top and two flanks and having threads, the two flanks defining a spiral groove having a bottom, And the first flank of the female thread facing the opposite side of the inlet of the hollow are pressed against each other while the pin is threaded into the hollow, a second flank of male threads directed towards the free end of the pin and a second flank The second flank of the female thread facing is pressed against each other while the pin is threaded out of the hollow portion and the first flank of the female thread and male thread is threaded into the first flange of the first thread, Tool angled at an angle to the central axis. The tool of claim 1, wherein the first angle of the first flank to the central axis is greater than or equal to 100 degrees. The tool of claim 1 wherein the first angle of the first flank to the central axis is at most 120 degrees. The tool according to claim 1, wherein the second angle of the second flank to the central axis is 115 ° or more. The tool of claim 1 wherein the second angle of the second flank to the central axis is at most 150 degrees. The tool according to claim 1, wherein at least a first angle of the first male flank of the male and female threads is the same size. The tool according to claim 1, wherein the second angle of the second flank of the male thread and the female thread is the same size. The tool of claim 1, wherein the second portion comprises a wear portion comprising a hard wear resistant material, the first portion comprising a body comprising a relatively soft material and the second portion comprising a tool . 9. The tool of claim 8, wherein the abrasive portion comprises a milling cutter body and the body includes a rotatable shaft. 10. The rotary machine according to claim 9, wherein the male pins of the milling cutter body include first and second external rotationally symmetrical guide surfaces disposed respectively in front and rear of the axial direction of the male screw, and the hollow portion of the shaft is provided with first and second Wherein the first outer guide surface interacts with the first inner guide surface and the second outer guide surface engages and interacts with the second inner guide surface. As part of the tool for chip removal machining,
A male screw disposed adjacent a free end of a male pin extending along a central axis, the male screw including a helical thread having a peripheral upper portion and a pair of opposing flanks, the flange defining a helical groove having a bottom portion , The first one of the pair of opposing flanks facing away from the free end of the pin and being inclined with respect to the central axis at a first angle smaller than the inclination of the second angle with respect to the central axis of the second flank of the pair of opposing flanks A portion of the tool for chip removal machining. 12. A portion of a tool according to Claim 11 for chip removal machining wherein the first angle to the central axis is at least 100 degrees. 12. A tool according to claim 11, wherein the first angle to the central axis is at most 120 degrees. 12. A part of a tool according to claim 11, wherein the second angle to the central axis is 115 DEG or more. 12. A part of a tool according to claim 11 for chip removal machining, wherein the second angle to the central axis is at most 150 degrees. 12. The tool of claim 11, wherein the second angle with respect to the central axis is greater than 15 degrees greater than the first angle with respect to the central axis.

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